I'm planning to get some mottled sculpin. I have a 55 gallon that I'm dedicating to this. I know the care requirements (ie. lots of oxygen, current, cool temps), but I have a few questions. First off, what can I keep them with? I've heard darters can become meals, but is there a way to keep the two together? Also, what is a good number of them for a 55? Also, depending on the possible tankmates, how many can I keep of what species with them?